NA6918-ZW-XL bearing: complete specifications & equivalents

Specification table

Source: catalog reference (HR1 2026-09-25) · extracted 2026-09-30

Parameters extracted from the official FAG Rolling Bearings catalogue (HR1 2026-09-25); FAG® is a trademark of Schaeffler Technologies AG & Co. KG, used here for identification only — mpnbase is not an authorized FAG/Schaeffler distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at schaeffler.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the NA6918-ZW-XL model number is decoded

envelope 90×125×63 mm: 90 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 17.5 mm radial section packed with small-diameter needle rollers C is 195 kN and C0 425 kN at the 90 mm seat; the C/C0 ratio of 0.46 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 125 mm outside diameter the fatigue load limit Cur is 76 kN, the limiting speed 4,400 r/min and the thermal reference speed 2,550 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.17 kN/mm and per millimetre of width 3.10 kN/mm — the reason 63 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.31 kg (2310 g), just 0.29 g per mm² of projected 125×63 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 90 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery This is the choice for OEM production on soft shafts: machine the 90 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 425 kN C0 rating still assumes full rigid support under both rings As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 76 kN Cur value. -ZW is the double-row needle-cage code; the two rows run on the same races and keep the unit separable and interchangeable with the single-row mounting space. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 125 mm outside diameter and 195 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 90 mm seat, and in planetary gear bearings the 2.31 kg mass is part of the rotor inertia calculation. Designers also specify it for copying and printing machine mechanisms, relying on the 63 mm width and the published 425 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.
• Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.
• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.